<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			var arr1 = [1,2,3,4];
			var arr2 = arr1;
			arr1.push(5);
			arr1 = [1,2];
			document.write(arr2);
		</script>
	</body>
</html>
